A service entrance with ________ connected conductor(s) is a 3-phase supply.

• A. four
• B. 10+
• C. one
• D. zero

Answer: (A)

A service entrance with four connected conductors is indeed classified as a 3-phase supply because it typically consists of three phase conductors and one neutral conductor. In a three-phase power system, the phase conductors carry the current that powers the loads, while the neutral conductor provides a return path for unbalanced current. This configuration allows for efficient power distribution and is commonly used in commercial and industrial settings, as well as in some larger residential applications.

The presence of four conductors signifies that the system can utilize all three phase wires simultaneously with the added capability of balancing loads effectively through the neutral. This setup is essential for ensuring that electrical systems operate efficiently and safely, particularly when large amounts of power are required. Understanding the conductor configuration is critical for anyone inspecting electrical systems, as it informs the inspector about the potential load handling and the need for adequate protective measures.